MS4A4A and neoplasm: In addition to canonical M2 markers (such as CD163, FOLR2, and MS4A4A), these M2-like macrophages expressed high levels of several cysteine cathepsins (CTSD, CTSL, and CTSB) and of the epithelial–mesenchymal transition (EMT) marker (FN1), which have previously been associated with tumor invasion and migration and have been implicated for potential targeted therapy (44–48).